Laminitis, or founder as it is commonly known, is an inflammation of the sensitive laminae in the feet of horses, more commonly occurring in the front feet. It is an extremely painful and disabling affliction sometimes rendering the horse useless in breeding or riding activities.
The causes of the affliction are varied, one of the more common causes being overfeeding of grain which has an adverse effect on the blood chemistry of the animal and results in inflammation of the laminae.
An excellent treatise of the affliction may be found in the Special Report on Diseases of the Horse, which was published in 1903 by the U.S. Department of Agriculture. Another excellent publication is titled Lameness in Horses by O. R. Adams, D.V.M., M.S. and published by Lea & Febiger, Philadelphia.
In the advanced stage, known as chronic laminitis, the inflammation in the sensitive laminae is so severe that the sensitive and horny laminae separate. This leaves the coffin bone no support within the hoof, so the horse's weight pushing down on the anterior (front) portion of the hoof causes the coffin bone to rotate downward. In some cases the rotation is so severe that the end of the bone pierces the bottom of the foot which necessitates destruction of the animal.